Modifying Internal QuTiP Settings

User Accessible Parameters

In this section we show how to modify a few of the internal parameters used by QuTiP. The settings that can be modified are given in the following table:

Setting	Description	Options
auto_tidyup	Automatically tidyup sparse quantum objects.	True / False
auto_tidyup_atol	Tolerance used by tidyup. (sparse only)	float {1e-14}
atol	General absolute tolerance.	float {1e-12}
rtol	General relative tolerance.	float {1e-12}
function_coefficient_style	Signature expected by function coefficients.	{“auto”, “pythonic”, “dict”}

Example: Changing Settings

The two most important settings are auto_tidyup and auto_tidyup_atol as they control whether the small elements of a quantum object should be removed, and what number should be considered as the cut-off tolerance. Modifying these, or any other parameters, is quite simple:

>>> qutip.settings.core["auto_tidyup"] = False

The settings can also be changed for a code block:

>>> with qutip.CoreOptions(atol=1e-5):
>>>     assert qutip.qeye(2) * 1e-9 == qutip.qzero(2)